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Start Preamble

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

Start Printed Page 34658

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: Two cases of a crack on a “dry” ADG [air driven generator] (Hamilton Sundstrand part number in the 761339 series), in the aft area of the strut and generator housing assembly, have been reported on CL-600-2B19 aircraft. The same part is also installed on CL-600-2C10, -2D15 and -2D24 aircraft. Investigation determined that the crack was in an area of the strut where the wall thickness of the casting was below specification, due to a manufacturing anomaly in a specific batch of ADGs. Structural failure and departure of the ADG during deployment could possibly result in damage to the aircraft structure. If deployment was activated by a dual engine shutdown, ADG structural failure would also result in loss of hydraulics for the flight controls. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-0550; Directorate Identifier 2009-NM-124-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on those comments.

We have lengthened the 30-day comment period for proposed ADs that address MCAI originated by aviation authorities of other countries to provide adequate time for interested parties to submit comments. The comment period for these proposed ADs is now typically 45 days, which is consistent with the comment period for domestic transport ADs.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

Transport Canada Civil Aviation, which is the aviation authority for Canada, has issued Canadian Airworthiness Directive CF-2009-27, dated June 8, 2009 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

Two cases of a crack on a “dry” ADG [air driven generator] (Hamilton Sundstrand part number in the 761339 series), in the aft area of the strut and generator housing assembly, have been reported on CL-600-2B19 aircraft. The same part is also installed on CL-600-2C10, -2D15 and -2D24 aircraft. Investigation determined that the crack was in an area of the strut where the wall thickness of the casting was below specification, due to a manufacturing anomaly in a specific batch of ADGs. Structural failure and departure of the ADG during deployment could possibly result in damage to the aircraft structure. If deployment was activated by a dual engine shutdown, ADG structural failure would also result in loss of hydraulics for the flight controls.

This directive gives instructions to check the part number of the installed ADG and, for ADGs with a part number in the 761339 series, the serial numbers of the ADG and strut and generator housing assembly are also to be checked. If these serial numbers are within specified ranges ***, a one-time fluorescent penetrant inspection of the ADG strut is required [and replacement of the ADG if necessary].

Note: For ADGs with serial numbers in the *** specified ranges, subsequent fluorescent penetrant inspections are required after each scheduled in-flight or on-ground functional check of the ADG and also after each unscheduled in-flight ADG deployment. These inspection requirements are not mandated in this directive but are specified in the approved maintenance program.

You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Bombardier has issued Alert Service Bulletin A601R-24-120, Revision C, dated April 20, 2009; and Alert Service Bulletin A670BA-24-020, Revision C, dated April 20, 2009. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design.

Differences Between This AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in Start Printed Page 34659general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.

We might also have proposed different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are highlighted in a NOTE within the proposed AD.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 1,073 products of U.S. registry. We also estimate that it would take about 1 work-hour per product to comply with the basic requirements of this proposed AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $91,205, or $85 per product.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify this proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

Subject

Reason

(e) The mandatory continuing airworthiness information (MCAI) states:

Two cases of a crack on a “dry” ADG [air driven generator] (Hamilton Sundstrand part number in the 761339 series), in the aft area of the strut and generator housing assembly, have been reported on CL-600-2B19 aircraft. The same part is also installed on CL-600-2C10, -2D15 and -2D24 aircraft. Investigation determined that the crack was in an area of the strut where the wall thickness of the casting was below specification, due to a manufacturing anomaly in a specific batch of ADGs. Structural failure and departure of the ADG during deployment could possibly result in damage to the aircraft structure. If deployment was activated by a dual engine shutdown, ADG structural failure would also result in loss of hydraulics for the flight controls.

This directive gives instructions to check the part number of the installed ADG and, for ADGs with a part number in the 761339 series, the serial numbers of the ADG and strut and generator housing assembly are also to be checked. If these serial numbers are within specified ranges ***, a one-time fluorescent penetrant inspection of the ADG strut is required [and replacement of the ADG if necessary].

Note:

For ADGs with serial numbers in the * * * specified ranges, subsequent fluorescent penetrant inspections are required after each scheduled in-flight or on-ground functional check of the ADG and also after each unscheduled in-flight ADG deployment. These inspection requirements are not mandated in this directive but are specified in the approved maintenance program.

Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Actions

(g) Do the following actions.

(1) Within 1,000 flight hours after the effective date of this AD or before the first scheduled ADG functional test after the effective date of this AD, whichever occurs first, inspect to determine the part number of the installed ADG. A review of the airplane maintenance records is acceptable in lieu of this inspection if the part number can be conclusively determined from that review.

(i) If a Hamilton Sundstrand ADG having part number 1711405 is installed, the strut thickness is within specification and no further action is required by this AD.

(ii) If a Hamilton Sundstrand ADG having a part number in the 761339 series is installed, within 1,000 flight hours after the effective date of this AD or before the first scheduled ADG functional test after the effective date of this AD, whichever occurs first, inspect to determine the serial number of the ADG. A review of the airplane maintenance records is acceptable in lieu of this inspection if the serial number can be conclusively determined from that review.

(A) If the serial number of the ADG is 2000 or higher, the strut wall thickness is within specification and no further action is required by this AD.

(B) If the serial number of the ADG is in the range 0101 through 1999 and symbol “24-3” is marked in the serial number block of the identification plate, the strut wall thickness is within specification, no further action is required by this AD.

(C) If the serial number of the ADG is in the range 0101 through 1999 and the symbol Start Printed Page 34660“24-3” is not marked in the serial block of the identification plate, within 1,000 flight hours after the effective date of this AD or before the first scheduled ADG functional test after the effective date of this AD, whichever occurs first, inspect to determine the serial number of the strut and generator housing assembly. A review of the airplane maintenance records is acceptable in lieu of this inspection if the serial number can be conclusively determined from that review.

(1) If the serial number of the strut and generator housing assembly is in the range 0001 through 2503, do a fluorescent penetrant inspection in accordance with paragraph (g)(2) of this AD at the times specified in paragraph (g)(2) of this AD.

(2) If the serial number of the strut and generator housing assembly is 2504 or higher, the strut wall thickness is within specification and no further action is required by this AD.

(3) If the serial number of the strut and generator housing assembly is not inspected or it is not possible to determine the serial number, do a fluorescent penetrant inspection in accordance with paragraph (g)(2) of this AD at the times specified in paragraph (g)(2) of this AD.

(2) For ADGs having a strut and generator assembly identified in paragraph (g)(1)(ii)(C)(1) or (g)(1)(ii)(C)(3) of this AD: Within 1,000 flight hours after the effective date of this AD or before the first scheduled ADG functional test after the effective date of this AD, whichever occurs first, do a fluorescent penetrant inspection for cracking of the ADG strut, and if any crack is found, before further flight, replace the ADG with a serviceable ADG, in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A601R-24-120, Revision C, dated April 20, 2009 (for Model CL-600-2B19 airplanes); or Bombardier Alert Service Bulletin A670BA-24-020, Revision C, dated April 20, 2009 (for Model CL-600-2C10, CL-600-2D15, and CL-600-2D24 airplanes).

(3) Fluorescent penetrant inspections accomplished before the effective date of this AD in accordance with any applicable service bulletin specified in Table 1 of this AD are considered acceptable for compliance with the corresponding fluorescent penetrant inspection specified in this AD.

Note 1:

For additional guidance on the ADGs specified in paragraphs (g)(1)(ii)(C)(1)and (g)(1)(ii)(C)(3) of this AD and the repetitive fluorescent penetrant inspections specified as part of the periodic ADG functional check procedure, refer to the applicable tasks identified in Table 2 of this AD. These tasks can be found in Part 2 -Airworthiness Requirements, Appendix A—Certification Maintenance Requirements (CMR) of the Bombardier (Canadair) Regional Jet Maintenance Requirements Manual, and the Bombardier CRJ Series Regional Jet Aircraft Maintenance Manual (AMM).

Table 2—Guidance for the Periodic ADG Functional Check Procedure

Bombardier, Inc. Model—

Task Number (No.)—

CL-600-2B19 airplanes

CMR Task No. C24-20-129-01 and AMM Task No: 24-23-01-720-803.

CL-600-2C10 airplanes

CMR Task No. 24-23-00-102 and AMM Task No. 24-23-01-720-802.

CL-600-2D15 and CL-600-2D24 airplanes

CMR Task No. 24-23-00-102 and AMM Task No. 24-23-01-720-802.

Note 2:

For additional guidance on the ADGs specified in paragraph (g)(1)(ii)(C)(1), and the fluorescent penetrant inspection necessary following each future unscheduled in-flight ADG deployment, refer to following task specified in Table 3 of this AD.

Note 3:

In Hamilton Sundstrand Service Bulletin ERPS10AG-24-3, the fluorescent penetrant inspection is referred to as a “Penetrant Check.”

FAA AD Differences

Note 4:

This AD differs from the MCAI and/or service information as follows: No differences.

Other FAA AD Provisions

(h) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Program Manager, Continuing Operational Safety, FAA, New York ACO, 1600 Stewart Avenue, Suite 410, Westbury, New York, 11590; telephone 516-228-7300; fax 516-794-5531. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.

(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.

(4) Special Flight Permits: Special flight permits, as described in section 21.197 and section 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199), are not allowed.